How often does life really imitate art? Let’s imagine that a writer has been commissioned to develop a comedic screenplay about the deeply serious business of how to classify and control drugs. The plot is likely to feature that staple slapstick character “the mad scientist,” and since Hollywood tends to choose Britons to portray its eccentrics and villains, the writer makes the scientist a British professor. What’s a good name for a nutty professor? Why not Professor Nutt? The problem with this scenario, as the writer discovers, is that there’s a real Professor Nutt, a campaigning British scientist who avers in a new study, Drug Harms in the U.K.,that if you’re looking for the most dangerous drug of all, you have to start with alcohol, which is more harmful even than heroin and crack cocaine. (More on Time.com: 4 Reasons Binge Drinking Is a Public Health Problem)

Nutt—his first name is David, and he holds the chair in neuropsychopharmacology at London’s Imperial College, a university globally renowned as a seat of scientific excellence—is not mad, though conservative columnists regularly question his sanity. He was sacked as an adviser to Britain’s last Labour government for challenging official policy to reclassify cannabis from a class C to a class B drug — boosting its threat level — and for suggesting that ecstasy, by contrast, should be downgraded from class A.

Nutt also outraged the establishment by comparing one of its favorite pursuits, horse-riding, to ecstasy use, in order to illustrate the way in which the risks of certain drugs were routinely and reflexively overstated. “Equasy” — equine addiction syndrome, in other words, riding — caused 10 deaths and more than 100 road accidents a year, he wrote in the Journal of Psychopharmacology in 2009. “Making riding illegal would completely prevent all these harms and would be, in practice, very easy to do…This attitude raises the critical question of why society tolerates — indeed encourages — certain forms of potentially harmful behavior but not others, such as drug use.”

Generating splenetic headlines isn’t Nutt’s aim. Generating debate is. His research into the damage caused by drugs, and the legislative framework designed to minimize these harms, has instilled in him a passionate belief that drug policy needs to be more firmly based on scientific evidence. (More on Time.com: 7 Tips for California: How to Make Legalizing Marijuana Smart)

“By legislating on a substance without reliable scientifically based evidence, we run the risk of causing more harm through criminalizing users than might be caused by the drug itself,” he writes in the latest post on his personal blog, Evidence not Exaggeration. “The evidence on drug harms should not be sacrificed for political and media pressure.”

That’s the spirit behind his new study, authored with Leslie King and Lawrence Phillips and newly published in the medical journal, The Lancet. By analyzing the impact of 20 drugs in terms of 16 criteria highlighting their effect on users (health issues, dependency, mental impairment, loss of tangibles such as job, loss of relationships, injury) and on the people and society they interact with (crime, degradation of local environment, family strains, and wider issues such as economic cost), Nutt produced a ranking. He found that alcohol was the most harmful drug overall — and anyone who has seen the Saturday night transformation of British city centers into battlegrounds of blood and vomit will understand this point — followed by heroin and crack cocaine. Heroin, crack cocaine and methamphetamine proved the most injurious to the individuals using the drugs. Cannabis ranked 8th most harmful, after two legal drugs, alcohol and tobacco. (More on Time.com:Marijuana as Gateway Drug: The Myth That Will Not Die)

Booze and cigarettes do “have commercial benefits to society in terms of providing work and tax, which to some extent offset the harms,” notes the report, while concluding that “aggressively targeting alcohol harms is a valid and necessary public health strategy.” The report also admits that “many of the harms of drugs are affected by their availability and legal status.”

That’s a key point likely to be picked up by critics of any moves to decriminalize marijuana, who say the social harms of the drug would increase in proportion to its availability. The voters of California will put that view to the test if they decide to support Proposition 19 in tomorrow’s ballot.